It’s Halloween, and right on lightning-flash cue enters an operatic ghost story exhumed from the grave of long-since-buried works. You couldn’t hope for more discerning grave-robbers than Wexford Festival Opera, however, who have long made it their mission to bring forgotten operas back to life. Mascagni’s Guglielmo Ratcliff is a proper blood-on-the-tartan gothic thriller, all duels, doomed lovers, fainting heroines and family curses, with a score as fleshy with tunes as the composer’s more famous Cavalleria rusticana — think Lucia di Lammermoor without the fey bel canto warblings.